A ChannelHandler that adds support for writing a large data stream asynchronously neither spending a lot of memory nor getting OutOfMemoryError. Large data streaming such as file transfer requires complicated state management in a ChannelHandler implementation. ChunkedWriteHandler manages such complicated states so that you can send a large data stream without difficulties.

To use ChunkedWriteHandler in your application, you have to insert a new ChunkedWriteHandler instance:

ChannelPipeline p = ...;
p.addLast("streamer", new ChunkedWriteHandler());
p.addLast("handler", new MyHandler());

Once inserted, you can write a ChunkedInput so that the ChunkedWriteHandler can pick it up and fetch the content of the stream chunk by chunk and write the fetched chunk downstream:

Channel ch = ...;
ch.write(new ChunkedFile(new File("video.mkv"));

Sending a stream which generates a chunk intermittently

Some ChunkedInput generates a chunk on a certain event or timing. Such ChunkedInput implementation often returns null on ChunkedInput#readChunk(ChannelHandlerContext), resulting in the indefinitely suspended transfer. To resume the transfer when a new chunk is available, you have to call resumeTransfer().

Nested and Inner Type Summary

Modifier and Type	Class and Description
private static class	ChunkedWriteHandler.PendingWrite

Field Summary

Modifier and Type	Field and Description
private volatile ChannelHandlerContext	ctx
private static final InternalLogger	logger
private Queue<ChunkedWriteHandler.PendingWrite>	queue

Constructor Summary

Access	Constructor and Description
public	ChunkedWriteHandler()
public	ChunkedWriteHandler(int maxPendingWrites) Deprecated use `ChunkedWriteHandler()`

Method Summary

Modifier and Type	Method and Description
private void	allocateQueue()
public void	channelInactive(ChannelHandlerContext ctx) Overrides io.netty.channel.ChannelInboundHandlerAdapter.channelInactive. Implements io.netty.channel.ChannelInboundHandler.channelInactive. Calls `ChannelHandlerContext#fireChannelInactive()` to forward to the next `ChannelInboundHandler` in the `ChannelPipeline`.
public void	channelWritabilityChanged(ChannelHandlerContext ctx) Overrides io.netty.channel.ChannelInboundHandlerAdapter.channelWritabilityChanged. Implements io.netty.channel.ChannelInboundHandler.channelWritabilityChanged. Calls `ChannelHandlerContext#fireChannelWritabilityChanged()` to forward to the next `ChannelInboundHandler` in the `ChannelPipeline`.
private static void	closeInput(ChunkedInput<?> chunks)
private void	discard(Throwable cause)
private void	doFlush(final ChannelHandlerContext ctx)
public void	flush(ChannelHandlerContext the `ChannelHandlerContext` for which the flush operation is made ctx) Overrides io.netty.channel.ChannelDuplexHandler.flush. Implements io.netty.channel.ChannelOutboundHandler.flush. Calls `ChannelHandlerContext#flush()` to forward to the next `ChannelOutboundHandler` in the `ChannelPipeline`.
private static void	handleEndOfInputFuture(ChannelFuture future, ChunkedInput<?> input, ChunkedWriteHandler.PendingWrite currentWrite)
private void	handleFuture(ChannelFuture future, ChunkedInput<?> input, ChunkedWriteHandler.PendingWrite currentWrite, boolean resume)
public void	handlerAdded(ChannelHandlerContext ctx) Overrides io.netty.channel.ChannelHandlerAdapter.handlerAdded. Implements io.netty.channel.ChannelHandler.handlerAdded. Gets called after the `ChannelHandler` was added to the actual context and it's ready to handle events.
private boolean	queueIsEmpty()
public void	resumeTransfer() Continues to fetch the chunks from the input.
private void	resumeTransfer0(ChannelHandlerContext ctx)
public void	write(ChannelHandlerContext the `ChannelHandlerContext` for which the write operation is made ctx, Object the message to write msg, ChannelPromise the `ChannelPromise` to notify once the operation completes promise) Overrides io.netty.channel.ChannelDuplexHandler.write. Implements io.netty.channel.ChannelOutboundHandler.write. Calls `ChannelHandlerContext#write(Object, ChannelPromise)` to forward to the next `ChannelOutboundHandler` in the `ChannelPipeline`.

Inherited from io.netty.channel.ChannelDuplexHandler:: bind close connect deregister disconnect read

Field Detail

ctx	back to summary
private volatile ChannelHandlerContext ctx

logger	back to summary
private static final InternalLogger logger

queue	back to summary
private Queue<ChunkedWriteHandler.PendingWrite> queue

Constructor Detail

ChunkedWriteHandler	back to summary
public ChunkedWriteHandler()

ChunkedWriteHandler	back to summary
public ChunkedWriteHandler(int maxPendingWrites) Deprecated use `ChunkedWriteHandler()` Annotations @Deprecated

Method Detail

allocateQueue	back to summary
private void allocateQueue()

channelInactive back to summary

channelInactive	back to summary
public void channelInactive(ChannelHandlerContext ctx) throws Exception Overrides io.netty.channel.ChannelInboundHandlerAdapter.channelInactive. Implements io.netty.channel.ChannelInboundHandler.channelInactive. Doc from io.netty.channel.ChannelInboundHandlerAdapter.channelInactive. Calls `ChannelHandlerContext#fireChannelInactive()` to forward to the next `ChannelInboundHandler` in the `ChannelPipeline`. Sub-classes may override this method to change behavior. Annotations @Override

public void channelInactive(ChannelHandlerContext ctx) throws Exception

Overrides io.netty.channel.ChannelInboundHandlerAdapter.channelInactive.

Implements io.netty.channel.ChannelInboundHandler.channelInactive.

Doc from io.netty.channel.ChannelInboundHandlerAdapter.channelInactive.

Calls ChannelHandlerContext#fireChannelInactive() to forward to the next ChannelInboundHandler in the ChannelPipeline. Sub-classes may override this method to change behavior.

Annotations

@Override

channelWritabilityChanged back to summary

channelWritabilityChanged	back to summary
public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception Overrides io.netty.channel.ChannelInboundHandlerAdapter.channelWritabilityChanged. Implements io.netty.channel.ChannelInboundHandler.channelWritabilityChanged. Doc from io.netty.channel.ChannelInboundHandlerAdapter.channelWritabilityChanged. Calls `ChannelHandlerContext#fireChannelWritabilityChanged()` to forward to the next `ChannelInboundHandler` in the `ChannelPipeline`. Sub-classes may override this method to change behavior. Annotations @Override

public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception

Overrides io.netty.channel.ChannelInboundHandlerAdapter.channelWritabilityChanged.

Implements io.netty.channel.ChannelInboundHandler.channelWritabilityChanged.

Doc from io.netty.channel.ChannelInboundHandlerAdapter.channelWritabilityChanged.

Calls ChannelHandlerContext#fireChannelWritabilityChanged() to forward to the next ChannelInboundHandler in the ChannelPipeline. Sub-classes may override this method to change behavior.

Annotations

@Override

closeInput	back to summary
private static void closeInput(ChunkedInput<?> chunks)

discard	back to summary
private void discard(Throwable cause)

doFlush	back to summary
private void doFlush(final ChannelHandlerContext ctx)

flush back to summary

flush	back to summary
public void flush(ChannelHandlerContext ctx) throws Exception Overrides io.netty.channel.ChannelDuplexHandler.flush. Implements io.netty.channel.ChannelOutboundHandler.flush. Doc from io.netty.channel.ChannelDuplexHandler.flush. Calls `ChannelHandlerContext#flush()` to forward to the next `ChannelOutboundHandler` in the `ChannelPipeline`. Sub-classes may override this method to change behavior. Parameters ctx:ChannelHandlerContext Doc from io.netty.channel.ChannelOutboundHandler.flush. the `ChannelHandlerContext` for which the flush operation is made Annotations @Override Exceptions Exception: Doc from io.netty.channel.ChannelOutboundHandler.flush. thrown if an error occurs

public void flush(ChannelHandlerContext ctx) throws Exception

Overrides io.netty.channel.ChannelDuplexHandler.flush.

Implements io.netty.channel.ChannelOutboundHandler.flush.

Doc from io.netty.channel.ChannelDuplexHandler.flush.

Calls ChannelHandlerContext#flush() to forward to the next ChannelOutboundHandler in the ChannelPipeline. Sub-classes may override this method to change behavior.

Parameters

ctx:ChannelHandlerContext

Doc from io.netty.channel.ChannelOutboundHandler.flush.

the ChannelHandlerContext for which the flush operation is made

Annotations

@Override

Exceptions

Exception:

Doc from io.netty.channel.ChannelOutboundHandler.flush.

thrown if an error occurs

handleEndOfInputFuture	back to summary
private static void handleEndOfInputFuture(ChannelFuture future, ChunkedInput<?> input, ChunkedWriteHandler.PendingWrite currentWrite)

handleFuture	back to summary
private void handleFuture(ChannelFuture future, ChunkedInput<?> input, ChunkedWriteHandler.PendingWrite currentWrite, boolean resume)

handlerAdded back to summary

handlerAdded	back to summary
public void handlerAdded(ChannelHandlerContext ctx) throws Exception Overrides io.netty.channel.ChannelHandlerAdapter.handlerAdded. Implements io.netty.channel.ChannelHandler.handlerAdded. Doc from io.netty.channel.ChannelHandler.handlerAdded. Gets called after the `ChannelHandler` was added to the actual context and it's ready to handle events. Annotations @Override

public void handlerAdded(ChannelHandlerContext ctx) throws Exception

Overrides io.netty.channel.ChannelHandlerAdapter.handlerAdded.

Implements io.netty.channel.ChannelHandler.handlerAdded.

Doc from io.netty.channel.ChannelHandler.handlerAdded.

Gets called after the ChannelHandler was added to the actual context and it's ready to handle events.

Annotations

@Override

queueIsEmpty	back to summary
private boolean queueIsEmpty()

resumeTransfer	back to summary
public void resumeTransfer() Continues to fetch the chunks from the input.

resumeTransfer0	back to summary
private void resumeTransfer0(ChannelHandlerContext ctx)

write back to summary

write	back to summary
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception Overrides io.netty.channel.ChannelDuplexHandler.write. Implements io.netty.channel.ChannelOutboundHandler.write. Doc from io.netty.channel.ChannelDuplexHandler.write. Calls `ChannelHandlerContext#write(Object, ChannelPromise)` to forward to the next `ChannelOutboundHandler` in the `ChannelPipeline`. Sub-classes may override this method to change behavior. Parameters ctx:ChannelHandlerContext Doc from io.netty.channel.ChannelOutboundHandler.write. the `ChannelHandlerContext` for which the write operation is made msg:Object Doc from io.netty.channel.ChannelOutboundHandler.write. the message to write promise:ChannelPromise Doc from io.netty.channel.ChannelOutboundHandler.write. the `ChannelPromise` to notify once the operation completes Annotations @Override Exceptions Exception: Doc from io.netty.channel.ChannelOutboundHandler.write. thrown if an error occurs

public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception

Overrides io.netty.channel.ChannelDuplexHandler.write.

Implements io.netty.channel.ChannelOutboundHandler.write.

Doc from io.netty.channel.ChannelDuplexHandler.write.

Calls ChannelHandlerContext#write(Object, ChannelPromise) to forward to the next ChannelOutboundHandler in the ChannelPipeline. Sub-classes may override this method to change behavior.

Parameters

ctx:ChannelHandlerContext

Doc from io.netty.channel.ChannelOutboundHandler.write.

the ChannelHandlerContext for which the write operation is made

msg:Object

Doc from io.netty.channel.ChannelOutboundHandler.write.

the message to write

promise:ChannelPromise

Doc from io.netty.channel.ChannelOutboundHandler.write.

the ChannelPromise to notify once the operation completes

Annotations

@Override

Exceptions

Exception:

Doc from io.netty.channel.ChannelOutboundHandler.write.

thrown if an error occurs

io.netty.handler.stream back to summary

private final Class ChunkedWriteHandler.PendingWrite

Class Inheritance

extends Object

java.lang.Object
io.netty.handler.stream.ChunkedWriteHandler.PendingWrite

Field Summary

Modifier and Type	Field and Description
pack-priv final Object	msg
pack-priv final ChannelPromise	promise

Constructor Summary

Access	Constructor and Description
pack-priv	PendingWrite(Object msg, ChannelPromise promise)

Method Summary

Modifier and Type	Method and Description
pack-priv void	fail(Throwable cause)
pack-priv void	progress(long progress, long total)
pack-priv void	success(long total)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

msg	back to summary
pack-priv final Object msg

promise	back to summary
pack-priv final ChannelPromise promise

Constructor Detail

PendingWrite	back to summary
pack-priv PendingWrite(Object msg, ChannelPromise promise)

Method Detail

fail	back to summary
pack-priv void fail(Throwable cause)

progress	back to summary
pack-priv void progress(long progress, long total)

success	back to summary
pack-priv void success(long total)

public Class ChunkedWriteHandler

Sending a stream which generates a chunk intermittently

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private final Class ChunkedWriteHandler.PendingWrite

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail